Assessment of Long-term Variability on Rainfall Distribution and Extreme Flash Flood Events in the Semi-Arid Region of El Paso, Texas

Climate change is expected to significantly impact rainfall patterns and extreme events such as flash floods worldwide. Cities in semi-arid regions, such as El Paso, Texas, are becoming more vulnerable to flash flooding due to rapid urbanization, dense and complex infrastructure, and changes in precipitation patterns caused by climate change. This study aimed to investigate two major flash flood events that occurred on August 01, 2006, and August 12, 2021, in El Paso. The working hypothesis is that long-term climate variability may affect flash floods associated with precipitation distribution. The study will focus on evaluating rainfall patterns and rain rates using ground measurements from the National Weather Service (NWS), NCEP/EMC Stage IV precipitation analysis, Multi-Radar/Multi-Sensor System (MRMS), and Continuous Ambient Monitoring Stations (CAMS) operated by the Texas Commission on Environmental Quality (TCEQ). We also perform numerical experiments using the Model for Predictions Across Scale (MPAS) and/or Weather Research and Forecasting (WRF) to assess their sensitivity on short-range rainfall prediction. The city's historical rainfall data and assessed flash flood events' current frequency and severity will be examined. CAMS stations' data throughout the city provided critical information about precipitation distribution. The preliminary findings suggest that the region's average annual rainfall may decrease, with an increase in intense rainfall events and associated flash flooding.